Debian DEB file creation query

[AndrewCot]

I have finally got my setup to be able to build the Debain DEB files using the SF SVN trunk source code.
But one of the files it outputs has a ddeb extension instead of the deb. The file with the strange extension is:
    codeblocks-libwxcontrib0-dbgsym_20.03svn<SVN#>_amd64.ddeb
The rest of the 16 deb files created have the correct deb extension.
Is this right or not? If it is not right  anyone got any ideas on where to look to see why this is occurring?